(in the plural) The Collationes Patrum in Scetica Eremo Commorantium by John Cassian, an important ecclesiastical work. (Now usually with capital initial.) [from 13th c.]

1563, John Foxe, Acts and Monuments, vol. 2, p. 55:

A certain abbot, named Moses, thus testifieth of himself in the Collations of Cassianus, that he so afflicted himself with much fasting and watching, that sometimes, for two or three days together, not only he felt no appetite to eat, but also had no remembrance of any meat at all […]

A reading held from the work mentioned above, as a regular service in Benedictine monasteries. [from 14th c.]

1843, TD Fosbroke, British Monachism, p. 52:

When the hymn was over the Sacrist was to strike the table for collation, and the Deacon to enter with the Gospel, preceded by three converts, carrying the candlestick and censer.

The light meal taken by monks after the reading service mentioned above. [from 14th c.]